Fume hood can be generally described as a ventilated working space for catching, accommodating and discharging exhaust air, hazardous gas and particulate matter. Most of the traditional fume hoods are used to send a large amount of environmental air from the front opening of the fume hood into the work chamber of the fume hood while using a blower of large power to exhaust air in the work chamber to accommodate and process hazardous substances in the air. Under the design concept of the traditional fume hoods, the higher the air volume sent in from the front opening, the more effective the controlling and discharging function of the fume hood to the hazardous substances in the air is, thus, it is required to supply a large amount of air to the space of the fume hood through the ventilation air conditioning system of the building, such as the laboratory, to replace the environmental air sent into the fume hood from the front opening. Due to that the air supplied into the laboratory belongs to a part of the environmental air supplied for the laboratory, it must be processed into the same environmental air degree so as to ensure a comfortable and secure working environment of the laboratory, therefore, the use of the traditional fume hoods usually causes a great energy consumption of the buildings where laboratories and others are. Besides, unpredictable and inconsistent air flowing modes, such as the vortex type air group near the air outlet and the front opening will often happen. Under this situation, whatever the air velocity sent into from the front opening is, it will cause the risk of air leakage in the work chamber if the air system in the work chamber has turbulence or vortex, and it will threaten the health and safety of the experimenters. Therefore, new fume hood design structure and operation technology is highly required to cut down the energy consumption and reduce the leakage risk of hazardous substances in the work chamber.
At present, new type energy-saving and environment protective fume hoods in the fume hood market are all air supply type fume hoods. By disposing an air supply outlet on the upper or lower side of the work chamber and obtaining supplement air from the air supply power system of the building to blow into the work chamber of the fume hood, above design saves the air conditioning energy consumption of the building caused by air supplied in a certain degree. However, the single supplement air flow of current new type fume hoods cannot establish a stable air flow mode in the work chamber of the fume hood, so the problem of air turbulence and vortex is still unsolved, the leakage risk hazardous to the health and safety of the experimenters still exists. Besides, current fume hoods in the market all rely on the unified air supply system and air exhaust system of the building to obtain power, if a plurality of fume hoods are used at the same time, the amount of air supplied cannot realize individual adjustment depending on the required use condition, thus it will cause the result of a higher energy consumption. Moreover, during the installation and debugging process, the fume hood and its control system often use components in bulk to be temporarily assembled on site, therefore, it has the problem of high installation cost and poor consistency of product quality.